Fig. 4. Telomerase expression. Lane A, TSR8 quantitative control; Lane B, pStro1+ cells; Lane C, telomerase-positive control; Lane D, LTR-9 line P18; Lane E, LTR-9 line P115; Lane F, SV40–56 line P17; Lane G, SV40-56 line P105; Lane H, {alpha}SM-56 line P30; Lane I, {alpha}SM-56 line P105. These experiments were performed three times with similar results. A representative gel is shown. pStro1+ nontransformed cells were used as a negative control (B), as well as the heat-treated extract (data not shown).